Switch



vJuly 1930.

D. cs. TAYLOR SWITCH Filed Aug. 10, 1929 In yaw/01 DAN/EL (i 72W. 0

resented M 1, i930 a: ",NITE stares PATNT DANIEL G. TAYLOR, 0F MINNEAPOLIS, MINNESOTA, ASSIG-NOR T0 'MINNEAPOLIS- HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS. MINNESOTA, A CORPORA- TION OF DELAWARE swrrcn Application filed August 10, 1929. Serial No. 384,974.

This invention relates to improvements in electric switch constructions, and has for one of its objects to provide an improved construction for reducing arcing to the minimum. The invention finds valuable application in switches of the snap 0r over-thecenter type,'particularly when switch operation is controlled by a relatively slow moving means such, for example, as a thermostat. Where a switch operating or control element is in turn controlled by such a slow moving means, there comes a time just before the control element moves from one control position to another, when the whole system is in a condition of unstable equilibrium, and in which the control members are therefore conditioned to vibrate in a manner to successively make and break the circuit. It is well known this vibratory movement causes arcing, and

- springs, in which there is no current carried through delicate knife edges of the system or through any of the pivotal points or through springs.

Features relate to: means operable to unfailingly prevent arcing and fusing as. the result of vibratory condition of the control elements, or of the contact elements; a device well adapted for use in connection with the thermal devices of heat regulating systems; and arrangement of the switch elements in reference to the control element so that while one portion of the control element engages the stop the other engages the control element in a manner to unfailingly secure it in a given switch controlling position such that vibratory movement of the control element substantially does not affect the movement of the control switch element, until sufiicient tension has been created to assure a quick circuit breaking motion of the switch or of the switch control element.

Features of the invention also include all details of construction, as well as combinations and sub-combintions of the parts.

Objects, advantages and features of the invention will appear in the description of the drawings forming a part of this application, and in said drawings:

Figure 1 is a face view showing the switch control element at inoperative position;

Figure 2 is a view similar to Figure 1 showing the switch control element in switch holding position, and showing the switch control element and a portion ofits mounting in section; and

Figure 3 is a vertical section substantially on line 3-3 of Figure 1.

Numeral 1 indicates a suitable base, which may be attached to a suitable panel, not shown. Mounted upon the base is aswit'ch comprising element 2 having an angular extension 3 forming a stop, and a movable element 4 having an extension 5 (adjacent extension 3) with which a switch control element, later to be described, is engaged to, in this instance, open the switch. The elements 3 and 5 aresubstantially parallel when the switch is closed as in Figure 1. The top of element 5 is at a level below the top of element 3 to provide a kind of recess for the reception of roller 25. The switch elements are mounted upon and secured to a suitable insulating element 6. Binding screws 7 secure terminal wires 8 and 9 to respective conducting elements 24. A second element 10 mounted on a suitable bracket 11 has an extension 12 which, with the extension 3. provides a pair of stops, with which a portion of a swingable switch control element now to be described, alternately engages.

The switch control element generally designated 13 is best illustrated in Figure 3, and includes a U-shaped upper portion having knife edge extensions 14 engaging in suitable bearings 15 of plates 1 and 16. Means for yieldably holding the switch control element at any switch control position is indicated at 17, and includes a spring attached at one end as at 18 to the control element, and at the opposite end as at 19 to a lever 20 pivoted as at 21 to frame plates 1 and 16. The spring 17 also acts to secure the knife edges inoperative relation, and motion of the control element in an axial direction is prevented by engagement of the edge faces 22 with plates 1 and 16. It will be seen that this spring will hold the switch control ele ment 1n each stop-engaged position and that by rocking movement of the element 20 the tension of the spring can be increased and its connecting point 19 moved backwardly and forwardly across line A to vary the tension and alternately swing element 13 in opposite directions to obtain a snap or over-thecenter action. In Figure 1, it is assumed that the element 21 is moving in direction of the arrow B and is at that stage in its movement where the control element 13 will shortly move away from the stop. In Figure 2, the movement is assumed to be in pro ress in direction of the arrow C. As posltioned in Figure 2, the moving parts may be presumed to be in a condition of unstable equilibrium as where there is a minimumtension of the spring 17 and therefore, where the element 13 has a tendency to vibrate or swing alternately in a direction away from and back to the stop 3. -It will be noted that although this swing may take place, and althou h this vibratory motion of the lower end 0% the element 13 may take place, the osition of element 5 will substantially not changed until the tension of the spring 17 is suflicient to positively and quicklyrelease this element 5 for an automatic movement to another switch control position, in this instance to close. A valuable feature of the invention is the use of the roller 25 (as part of the switch control element) piyoted as at 26 at the lower end of the element 13. Another valuable feature is the relation of the engaging points of this roller respectively with the elements 3 and 5. It will be noted that points of engagement of the switch and switch control-elements (when the parts are positioned as in Figure 2) lie on a line substantially passing through the center of swing of the control element, and on a line substantiallyperpendicular tothe points of engagement of stop 3 and roller 25 of control element 13. Means may be provided for adjusting the distance between the stops 3-12 to vary the degree of swinging motion.

When the switch arm 4 is at the control position shown in Figure 1, and when the con trol element is disengaged, the switch is, in this instance, closed, and the upper end of the extension 5 lies above or across a line B tangent to the lower surface of the roller memes thereafter positively held with the spring acting to hold the roller 15 firmly against the element 3, until a reverse movement of the lever 20 takes place and the tension of the spring gradually changes as the movement in the direction ofthe arrow C proceeds. It will be understood that element 20 may be controlled by a slow moving element such as a thermal device. This device has not, however, been shown. The invention herein finds a particularly useful embodiment in combi nation with slow-movement control systems.

A device is, therefore, provided in which a control element is adapted to swing toward a movable switch element, engage it, move it to one control po ition. and secure it at that control positiomand in which the point of engagement of the control and switch elements are substantially on a line which passes through the center of swing of the control element and at which time the element engages the stop to prevent further movement, and in which means is provided to yieldably hold the control element against the stop and in switch-securing position.

Although the construction has not been illustrated in the drawing, it is conceivable that the elementlO could have associated therewith an element the equivalent of 4 and 5, so that when the control arm had assumed the position shown in Figure 1, it could also be controlling a second switch. The arrangement would then be such that two switches were alternately moved to other switch control positions.

I claim as my invention:

1. A stop, a switch control element adapted. to swing and having a roller engageable with the stop, means for yieldably holding the switch control element against the stop, and a movable switch element adapted to be engaged by said roller, and moved to and be held in one switch control position by the time said roller has engaged said stop.

2. A switch having a movable element, a control element adapted to swing toward, engage, and secure the switch element in one control position, the points of engagement of the control and switch elements when securing the switch being substantially on a line which passes through the center of swing of the control element, and a stop with which the control element is engaged to limit its motion at switch-securing position.

3. A switch having a movable element, a control element adapted to swing toward said switch element, and having a roller adapted to engage the switch element and move it to and secure it in one control position, the points of engagement of the roller and switch elements, when securing the switch, being substantially on a line which passes through the center of swing of the control element, and a stop with which the roller is engaged to limit its motion at switch-secur- 'ing position.

'4. A movable switch element and means to positively move it to and yieldably hold it at one switch controlposition, a control element adapted to swing toward, engage, and secure said switch element in one control position. the points of en agement of the control and switch elements eing substantially on a'line passing through the center of swing of the control element, and a stop with which said control element is engaged when in switch securing position.

5. A movable switch element and means to move it to and yieldably hold it in'one switch control position, a control element swingably mounted and adapted to engage the switch and move it to another control position against the action of said yieldable holding means, a stop engageable by said control element when holding the switch against the gaging points of swltch and control elements bemg on a line substantially passing through the center of swing of the control element,

and on a line substantially perpendicular to the points of engagement of stop and control element.

I 7. A movable switch element and means to move it to and yieldably hold it in one switch control position, a control element swingably mounted and having a roller adapted to move the switch to another control position against the action of said yieldable holding means, a stop engageable by said roller when holding the switch against the action of said yieldable means, the engaging points of roller and control elements being on a line substantially passing through the center of swing of the control element, and through the rotative axis of the roller. 8. Apair of stops, a switch control element adapted to swing and alternately engage the stops, meansfor yieldably holding said switch control element at each stopengaged position, a movable switch element adapted to be moved to, and held in one switch control position by the time said control element has engaged one of the stops, the points of engagement of said control and switch element at this time bein substantiall on a line which passes throug the center 0 swing of the element,

'9. A pair of stops, a switch control element adapted to swing and having a roller alternately engageable with the stops, means 'for yieldably holding said switch control element at each stop-engaged position, a movable switch element adapted to be moved to and held in one switch control position by the time said roller has engaged one of the stops, the points of engagement of said roller and switch element at this time being substantially on a line which passes through the center of swing of the element, and

' through the rotative axis of the roller.

10. A pair of stops, a switch control element adapted to swing and having a roller a1- ternately engageable with the stops, means for yieldably holding said switch control element at each stop-engaged position, and a movable switch element adapted to be moved to and held in one switch control position by the time said roller'has engaged one of the stops.

In witness whereof I have hereunto set my hand this 3d day of August, 1929.

' DANIEL G. TAYLOR, 

